Phase change memories use phase change materials to accomplish electronic data storage. Phase change materials can typically be electrically switched between generally amorphous and generally crystalline states. Some materials may be electrically switched to a number of detectable degrees or orders of crystallinity that fall on the spectrum bounded by completely amorphous and completely crystalline states. Typical materials suitable for such an application include various chalcogenide elements. One useful property of phase change materials is that they are non-volatile. When the memory is set in a specific state of crystallinity representing a resistance value, that value is retained until the memory is reprogrammed, even if power is removed. This is because the program value can be assigned to each phase or physical state of the material (e.g., crystalline or amorphous or some degree in between).
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope or to specific invention embodiments is thereby intended.